646711840 has 24 divisors (see below), whose sum is σ = 1527857100. Its totient is φ = 258684672.

The previous prime is 646711837. The next prime is 646711843. The reversal of 646711840 is 48117646.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (646711837) and next prime (646711843).

It can be written as a sum of positive squares in 2 ways, for example, as 590101264 + 56610576 = 24292^2 + 7524^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 646711840.

It is not an unprimeable number, because it can be changed into a prime (646711843) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2020815 + ... + 2021134.

Almost surely, 2^646711840 is an apocalyptic number.

It is an amenable number.

646711840 is an abundant number, since it is smaller than the sum of its proper divisors (881145260).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

646711840 is a wasteful number, since it uses less digits than its factorization.

646711840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4041964 (or 4041956 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 37.

The square root of 646711840 is about 25430.5296838269. The cubic root of 646711840 is about 864.7759518632.

The spelling of 646711840 in words is "six hundred forty-six million, seven hundred eleven thousand, eight hundred forty".